Electrical switch control



Dec. 28; 1943.

INVENTQR I A 28 Hmm Fig-5 Patented Dec. 28, 1943 UNITED STATES PATENT OFFICE.

ELECTRICAL SWITCH CONTROL William L. Guunmn, St. Petersburg, Fla. Application June 15, 1940, Serial No. 340,843

' 8 Claims. (01.175-337) This invention relates to solenoid-operated devices which are used to cause the opening of a switch, and more particularly to equipment which opens a switch only after a predetermined number of successive overloads have occurred.

One use for the invention is in sectionalizing distribution or transmission lines. One object is to provide equipment whereby heavy momentary surges will not cause the line to be opened, provided normal conditions are re-established immediately thereafter; but the equipment will open the line if the fault proves to be permanent and normal conditions cannot be re-established by deenergizing and then reenergizing the line.

The principles disclosed in 'the invention may be used to operate a wide variety of circuit opening devices, and the current for the solenoid may be the line current itself, or it may come from the secondary circuit of a current transformer.

In the drawing, Figure 1 shows a diagram of one type of circuit in which this invention is used;

. Figure 2 is a cross-section of the deviceitself.

and Figures 3, 4 and show details of certain parts of the device. Power comes from the source through an oil circuit breaker, 0.0. B.

The circuit breaker i is connected in the line 2, which also goes through the currentt'ransformer I.

The secondary circuit of the transformer 3 goes through the coil of the device 4, and when the predetermined conditions have occurred the plunger 5 lifts and trips the latch 6 thereby releasing the breaker I so that it opens the circuit.

The device 4 is shown in partial section and in larger scale in Figure 2, in which the coil 1 surrounds the mechanism which is inside the split brass tube 8. The magnetic circuit includes the endvpiece 8, the collar II, the rings l2 and I3, the stationary sleeve 14, the movable plunger IS, the ratchet l6, and the hollow cylinder ii. Integral with the iron plunger I5 is the split brass cylinder II, and the ratchet I6 is part of the assembled plunger unit which is free to move up and down between the sleeve l4 and the cylinder l1. FiguresYS, 4 and 5 show the plunger parts in larger scale. The operating rod 5 carries the pushes against the tooth 24 ratchet member biases the plunger sleeve 29.

Operation is as follows. When an overload having at least a predetermined minimum amperage occurs, the plunger I5 is drawn downwardly until it is stopped by the cylinder l1. This compresses spring 26 and also closes the gap between 15 .and I1 without breaking the magnetic circuit between the plunger I5 and the sleeve i4. At the same time, the ratchet i6 is pulled by magnetic flux outwardly against the inner wall of cylinder 11, against the bias of spring 28.

When the overload ceases suddenly and completely, as by the opening of a circuit breaker O. C. B, nearer to the power source, the spring 28 pulls the tooth '23 into the groove 20 so that the rod I moves upward with plunger 15 under pressure of the. spring 26. When the source breaker is reclosed and the same overload again imposed on the coil, the ratchet I8 is instantly time engages with the grooveZl.

guide collar l0 and the iron collar H, and at its lower end are the grooves 20, 2|, 22 which are capable of receiving the tooth 23 of the ratchet iii. The tooth 24 on the ratchet serves as a means whereby the manually operated rod 25 can force the ratchet outwardly and cause the tooth 23 to release the rod 5. The movable collar 30 and the rod 25 are pinned together; lifting the collar 30 by suitable means raises the rod 25 until it pulled outwardly, disengaging the groove 28. Also the plunger I5 is again pulled down to close the gap between lland ll. Meanwhile the heavy magnetic flux through the coil holds the ring! i in its position of bridging the collars l2 and I3, so that the rod 5 does not drop downwardly due to gravity.

A second sudden cessation of current flow again releases the ratchet l6, and the tooth 23 this The ratchet It has a short travel, and the spring 28 moves the ratchet before gravity has lowered the rod 5 too far forthe tooth 23 to engage groove 2|. Then the spring 26 again liftsthe plunger l5 and with it the rod 5. Upon the occurrence of the short circuit the third time, followed by the third sudden drop in current flow, the tooth 23 engages the groove 22 and the spring 26 lifts the rod 5 still higher so that it operates the latch 6 and opens the switch i.

Thus the device acts to open the line switch I only after the line has been three times subjected normally rests on the stationary the tooth23 from to an overload which was great enough to cause the source circuit breaker to open.

- switch I, normal current flow in line 2 will reset the device to its original normal condition. This automatic re-setting of the mechanism to normal condition isan important feature of this form of my invention. After the device has opened switch I as described above. it may be reset to normal by manually lifting the button 30 and thereby causing the tooth 23 to be disengaged from the grooves in rod 5.

Many modifications may be made without do parting from the purpose and spirit of this invention. The number of grooves, 20, 2i, 2!, in the rod 5 may be varied, thus causing the line breaker I to be opened after a diilerent number of successive overloads have occurred,

I claim: i

1. A switch tripping device comprising a solenoid, an armature forming part of a plunger within the solenoid, a spring biasing the plunger against the magnetic pull of the solenoid, a switch-tripping member movable within the plunger, and ratchet means within the solenoid and supported by the plunger spring pressed into engagement with said switch tripping member and magnetically released from engagement with said member in response toisuccessive energize.- tions of said lenoid.

2. A step by step relay comprising an operating coil. a spring pressed plunger movably responsive to current flow in the coil, a stepped trip rod, a latch carried by the said plunger and engageable with successive steps of the said trip rod when current flow ceases, together with magnetic holding means operable by excess current flow in the coil to hold the said trip rod stationary when the plunger moves in response to excess current flow.

3. A step by step relay comprising an operating coil, 9. spring pressed plunger within the coil and operable'by current flow in the coil, a

stepped trip rod within the coil coaxial with. and

'Iithin the solenoid, a spring biasing the plunger against the magnetic pull of the solenoid and operable to return the plunger to normal position, a switch-tripping member movable within the plunger and coaxial withit, magnetic holding means operable only by excess current flow in the solenoid to hold the said switch-tripping member stationary when the plunger moves in response to excess current flow, and connecting means operable by cessation of current flow in the solenoid to connect the plunger with the said switch-tripping member as the plunger is being returned to normal position.

5. A step by step relay comprising a solenoid, a biased armature operable by the solenoid away from its biased position, a movable member operable step by step by successive movements of the armature, ratchet means movable with said armature and engageable with said movable member and a magnetic device for holding the said movable member when the solenoid moves the armature, the said magnetic device comprising a multiplicity of spaced annular rings of magnetic material within said solenoid and at least one round member of magnetic material connected to the said movable member and movable within the said spaced annular rings to coordinate with them in successive positions.

6. Aston by step relay comprising a solenoid, a plunger within the solenoid spring biased in one direction and movable in the opposite direction responsive to flow'of current in the solenoid,

an operating member coaxially within theplunger and movable longitudinally of the plunger, a latch member within the solenoid, movable with the plunger, a spring biasing the latch into engagement with the said operating member, the said latch member being magnetically movable out of engagement with the said operating member by a predetermined flow of current in the solenoid.

7. A switch tripping device comprising a solenoid cofl, a magnetic plunger within the coil movably responsive to current flow in the coil and biased against the magnetic pull of the coil, 9. switch-tripping member within the coil and movable coaxially and longitudinally with the plunger, a magnetic clutch within the coil and travelling with the plunger and ensfls able with the switch-tripping member to move it in successive steps in response to successive energizations and deenergiaations of the coil, and means for bold- 1118 said switch tripping member in the positions gained by each step of its movement.

8. A step by step relay comprising a solenoid,

a biased armature operable by the solenoid away from its biased position, a movable member operable step by step by successive movements of the armature, ratchet means movable with said armature and engageable with'said movable member and a magnetic device for holding the said stepped member when the solenoid moves the armature, the said magnetic device comprising an annular ring of magnetic material carried by said movable member, spaced fixed members of magnetic material surrounding said movable member on opposite sides of said ring, said ring and said members of magnetic material being within said solenoid for establishing a magnetic held through said ring.

WILLIAM L. GARLINGTON. 

